U.S. patent number 4,692,200 [Application Number 06/907,108] was granted by the patent office on 1987-09-08 for self-venting balloon dilatation catheter and method.
This patent grant is currently assigned to Advanced Cardiovascular Systems, Inc.. Invention is credited to Philip E. Powell.
United States Patent |
4,692,200 |
Powell |
September 8, 1987 |
Self-venting balloon dilatation catheter and method
Abstract
Self-venting balloon dilatation catheter having a flexible
tubular member with first and second lumens extending therethrough.
An inflatable balloon is carried by the distal extremity of the
tubular member in such a manner so that the first lumen extends
through the balloon and is out of communication with the interior
of the balloon and the second lumen is in communication with the
interior of the balloon. A venting device is disposed between the
balloon and the tubular member for venting air from the interior of
the balloon but inhibiting the escape of liquid from the
balloon.
Inventors: |
Powell; Philip E. (Mountain
View, CA) |
Assignee: |
Advanced Cardiovascular Systems,
Inc. (Mountain View, CA)
|
Family
ID: |
27116845 |
Appl.
No.: |
06/907,108 |
Filed: |
September 15, 1986 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
760637 |
Jul 30, 1985 |
4638805 |
|
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Current U.S.
Class: |
156/289; 156/294;
604/913; 604/915; 606/192 |
Current CPC
Class: |
A61M
25/10 (20130101); A61M 25/104 (20130101); A61M
2025/1086 (20130101) |
Current International
Class: |
A61M
25/10 (20060101); A61M 29/02 (20060101); B29C
027/00 () |
Field of
Search: |
;156/289,294 ;128/344
;604/96,103 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Croyle; Carlton R.
Assistant Examiner: Olds; Theodore
Attorney, Agent or Firm: Flehr, Hohbach, Test, Albritton
& Herbert
Parent Case Text
This is a division of application Ser. No. 760,637, filed July 30,
1985, now U.S. Pat. No. 4,638,805.
Claims
What is claimed is:
1. In a method for fabricating a self-venting balloon dilatation
catheter, providing a first tubular element having a lumen
extending therethrough, providing a second tubular element having a
lumen disposed therein, forming a balloon onto the second tubular
element near the distal extremity of the second tubular element,
placing the first tubular element within the second tubular element
so that the second tubular element extends coaxially of the first
tubular element and forming a flow passage open to ambient between
the distal extremities of the first and second tubular elements and
in communication with the interior of the balloon which has a size
less than 0.001 inches to permit the escape of air from the
interior of the balloon but inhibiting the escape of liquid from
the interior of the balloon.
2. In a method for fabricating a self-venting balloon dilatation
catheter, providing a first tubular element having a lumen
extending therethrough, providing a second tubular element having a
lumen disposed therein, forming a balloon onto the second tubular
element near the distal extremity of the second tubular element,
placing the first tubular element within the second tubular element
so that the second tubular element extends coaxially of the first
tubular element, forming a flow passage between the distal
extremities of the first and second tubular elements and in
communication with the interior of the balloon which has a size
less than 0.001 inches to permit the escape of air from the
interior of the balloon but inhibiting the escape of liquid from
the interior of the balloon, said flow passage being formed by
introducing a wire between the distal extremities of the first and
second tubular elements, forming the second tubular element of a
heat shrinkable plastic, placing a mandrel in the lumen of the
first tubular element in the distal extremity of the first tubular
element, applying heat to the distal extremity of the second
tubular element to heat shrink it onto the first tubular element,
permitting the distal extremities of the first and second tubular
elements to cool, removing the mandrel from the lumen of the first
tubular element and removing the wire from between the first and
second tubular elements to provide the flow passage.
3. A method as in claim 2 wherein said wire is formed of tungsten
to facilitate the transfer of heat and to facilitate removal of the
wire.
Description
This invention relates to balloon dilatation catheters and more
particularly to such catheters having a self-venting balloon and a
method for making the same.
In utilizing balloon dilatation catheters, it is necessary that the
balloon be filled with a liquid. In the filling of the balloon, it
is desirable that the air which is within the balloon be expelled
from the balloon but the air is compressible. In the past this has
been accomplished by successively aspirating the balloon with
fluid. The air is withdrawn during the repeated evacuation. This
has a disadvantage in that it can be difficult to ensure complete
removal of all the air. Alternatively, the air removal is
accomplished by providing a separate tube which may be removable
which extends from the proximal extremity of the catheter into the
balloon so that during the time that the liquid is being introduced
into the ballon, the air in the balloon can be expelled through the
separate tube. The use of such a separate tube has a disadvantage,
particularly when it is desired to provide a dilatation catheter
which has a very low profile in that it makes it more difficult to
reduce the profile of the dilatation catheter. There is therefore a
need for a new and improved balloon dilatation catheter which
overcomes these limitations.
In general, it is an object of the present invention to provide a
balloon dilatation catheter which is self-venting.
Another object of the invention is to provide a dilatation catheter
of the above character in which the air is vented through the
distal extremity of the catheter.
Another object of the invention is to provide a balloon dilatation
catheter of the above character in which the air in the balloon is
vented while the leakage of any liquid from the balloon is
inhibited.
Another object of the invention is to provide a balloon dilatation
catheter of the above character which ensures complete removal of
the air without aspiration.
Another object of the invention is to provide a method for
constructing the catheter of the present invention.
Additional objects and features of the invention will appear from
the following description in which the preferred embodiment is set
forth in detail in conjunction with the accompanying drawing.
FIG. 1 is a side elevational view of a balloon dilatation catheter
incorporating the present invention.
FIG. 2 is a cross sectional view of the distal extremity of the
balloon dilatation catheter shown in FIG. 1.
FIG. 3 is a cross sectional view taken along the line 3--3 of FIG.
2.
FIG. 4 is a cross sectional view showing the method which is
utilized in manufacturing the balloon dilatation catheter shown in
FIGS. 1-3.
In general, the self-venting balloon dilatation catheter of the
present invention is comprised of a flexible tubular member having
first and second lumens extending therethrough. An inflatable
balloon is carried by the distal extremity of the tubular member in
such a manner so that the first lumen extends through the balloon
and is out of communication with the interior of the balloon and
the second lumen is in communication with the interior of the
balloon. A vent system is disposed between the balloon and the
tubular member for venting air from the interior of the balloon but
inhibiting the escape of liquid from the balloon.
More in particular as shown in FIGS. 1-3 of the drawing, the
balloon dilatation catheter 10 incorporating the present invention
is comprised of a tubular member 11 which consists of a first
tubular element 12 which has a lumen 13 extending therethrough. It
also consists of a second tubular element 14 which is coaxially
disposed on the first tubular element 12 and provides in
conjunction with the first tubular element an annular lumen which
extends longitudinally of the first and second tubular elements 12
and 14. An expandable balloon 17 is carried by the second tubular
element 14 of the member 11 near the distal portion thereof and has
its interior in communication with the lumen 16. The balloon 17
extends concentrically about the first tubular element 12. Although
the balloon 17 can be formed as a separate element which has its
extremities bonded to the second tubular element 14, it is
preferably formed integral with the second tubular element as
shown. The tubular elements 12 and 14 are formed of a suitable
flexible thermo-plastic material such as a polyolefin or
polyvinylchloride.
The distal extremities of the first and second tubular elements 12
and 14 are bonded together in a suitable manner so as to form a
liquid-tight seal between the same. Typically this can be
accomplished by applying heat to the distal extremity of the second
tubular element with a mandrel disposed in the distal extremity of
the first tubular element and applying heat to shrink the distal
extremity of the second tubular element onto the first tubular
element to form such a seal.
Means is provided in the distal extremity of the first and second
tubular elements for venting air from the balloon 17 while
inhibiting the escape of liquid from the balloon 17 and consists of
a very small passage 21 which is disposed between the distal
extremities of the first and second tubular elements 12 and 14 and
which extends from the interior of the balloon 17 to ambient at the
distal extremity of the catheter 11. The flow passage 21 can be
formed in any suitable manner. One method found to be particularly
efficacious is as follows in conjunction with FIG. 4. A piece 22 of
suitable wire such as tungsten is used because of its good tensile
strength. The wire 22 should have a diameter which is less than
0.001 inches as, for example, 0.0005 inches. It is coated with
silicone. After the wire 22 has been coated with silicone, it is
inserted by a tweezers between the distal extremities of the first
and second tubular elements 12 and 14 prior to the time that the
second tubular element 14 is heat shrunk onto the first tubular
element as hereinbefore described. As soon as the tungsten wire 22
has been inserted into the distal extremities of the first and
second tubular elements 12 and 14 so that it extends into the
balloon 17 and out the distal extremities as shown in FIG. 4, a
mandrel 23 is inserted into the lumen 13. Heat is then applied to
the distal extremity of the second tubular element 14 to cause it
to form a shrink fit between it and the distal extremity of the
first tubular element 12 and at the same time to shrink down around
the wire 22. After the distal extremity of the catheter has been
cooled, the mandrel 23 can be removed and the wire 22 can be pulled
out with tweezers leaving the cylindrical flow passage 21
hereinbefore described.
It should be appreciated that if desired, more than one hole or
passage 21 can be provided to make the balloon venting procedure
more rapid. It also should be appreciated that other means can be
provided in the distal extremity of the catheter in place of the
passage 21 for making the balloon 17 self-venting. For example,
braided fibers can be utilized in the distal extremity of the
catheter in the same manner as the tungsten wire 22 has been
utilized. In such a case, the fibers can be left in place so that
the air can flow between interstices of the braided fibers.
Alternatively, hollow fiber or fibers can be incorporated into the
distal extremity of the catheter. Alternatively, hydrophobic filter
material can be incorporated between the distal extremities of the
first and second tubular elements 12 and 14. This filter material
is capable of passing air but inhibits the passage of liquid from
the balloon 17.
The remainder of the balloon dilatation catheter shown in FIG. 1 is
substantially conventional. A side arm adapter 26 is provided which
has a main or central arm 27 and a side arm 28. A guide wire 29
extends through the main or central arm 27 and extends through the
lumen 13 of the first tubular element 12 and has a distal extremity
extending beyond the distal extremity of the dilatation catheter
11. A torquer 31 is secured to the proximal extremity of the guide
wire 29 and is utilized for extending and retracting the guide wire
and also for rotating the guide wire.
Use of the self-venting balloon dilatation catheter may now be
briefly described as follows. The balloon 17 is first inflated
outside of the human body by introducing a radiographic contrast
liquid through the side arm 28 so that is passes through the
annular lumen 16 between the first and second tubular elements 12
and 14 and passes into the balloon 17. The air which is in the
balloon is pushed forwardly in the balloon and under the pressure
of the radiographic contrast liquid is forced to pass out through
the small passage 21 provided between the distal extremities of the
first and second tubular elements 12 and 14. By utilizing a passage
21 having a diameter of 0.0005 inches, it has been found that a two
millimeter diameter balloon having a length of approximately 25
millimeters can be completely rid of air in less than approximately
40 seconds. The size of the passage 21 is such that it inhibits the
escape of the radiographic contrast liquid so that very little, if
any, of the liquid can escape, even though pressures up to 200 psi
for the radiographic contrast liquid is attained within the balloon
17. As soon as the balloon 17 has been inflated with the
radiographic contrast liquid and the air has been expelled
therefrom through the passage 21, the liquid can be withdrawn to
deflate the balloon 17. The balloon dilatation catheter is now
ready to be inserted into the human body. After the balloon 17 has
been positioned in the stenosis in the arterial vessel in the human
body, the balloon can be again inflated by reintroducing
radiographic contrast liquid through the side arm 28 through the
lumen 16 and into the balloon 17. Since all of the air has
previously been expelled from the balloon 17, the balloon can be
readily inflated within the stenosis to its full diameter at the
desired pressure as, for example, in excess of 100 psi without
danger of any significant amount of radiopaque contrast liquid
passing through the passage 21. After the opening in the stenosis
has been enlarged, the balloon can be deflated and the dilatation
catheter can be removed.
It is apparent from the foregoing that there has been provided a
balloon dilatation catheter which is self-venting and in which the
balloon can be inflated to the desired pressure without danger of
any significant amount of radiopaque contrast liquid passing
through the venting orifice provided in the distal extremity of the
balloon dilatation catheter. The venting orifice formed in the
distal extemity of the balloon dilatation catheter is formed in
such a manner so that it can be readily incorporated into the
manufacturing process for making the balloon dilatation
catheters.
* * * * *